Variable expansion frame system for deploying medical devices and methods of use

ABSTRACT

An expansion frame system for deploying medical devices in a patient&#39;s body cavity. The system typically includes an inner wire disposed within a lumen of an outer wire. Distal ends of the inner and outer wires are attached to a substantially circular frame at first and second points. During use, the outer wire is displaced relative to the inner wire, causing the circular frame to rotate about an axis perpendicular to the line defined by the first and second points. Medical devices, such as a filter, a stent, an occluder or a manometer, can be mounted on the circular frame. The diameter of the expansion frame can be varied to achieve optimal contact with the luminal wall of the body cavity. Methods of using the expansion frame system for temporary or permanent placement of a medical device is disclosed.

[0001] This is a continuation of U.S. application Ser. No. 09/365,991,filed Aug. 3, 1999, incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] The present invention relates generally to systems and methodsuseful for deploying medical devices within a body, such as a patient'sblood vessel. More specifically, the invention provides a variablediameter expansion frame system for temporary or permanent deployment ofmedical devices, such as a blood filter, a stent, a manometer, or anoccluder, in arteries or veins. The frame can be placed in a collapsedcondition to facilitate insertion of the device and in an expandedcondition to deploy the medical device. The diameter of the frame can bevaried to achieve maximal contact with the vascular wall.

BACKGROUND OF THE INVENTION

[0003] Treatment of thrombotic or atherosclerotic lesions in bloodvessels using the endovascular approach has recently been proven to bean effective and reliable alternative to surgical intervention inselected patients. For example, directional atherectomy and percutaneoustranslumenal coronary angioplasty (PTCA) with or without stentdeployment are useful in treating patients with coronary occlusion.These endovascular techniques have also proven useful in treating othervascular lesions in, for example, carotid artery stenosis, peripheralarterial occlusive disease (especially the aorta, the iliac artery, andthe femoral artery), renal artery stenosis caused by atherosclerosis orfibromuscular disease, superior vena cava syndrome, and occlusion iliacvein thrombosis resistant to thrombolysis.

[0004] It is well recognized that one of the complications associatedwith endovascular techniques is the dislodgment of embolic materialswhich can occur during manipulation of the vessel, thereby causingocclusion of the narrower vessels downstream and ischemia or infarct ofthe organ which the vessel supplies. There are a number of devicesdesigned to provide blood filtering for entrapment of vascular emboli inarteries. These devices have also been placed prophylactically, e.g., inthe inferior vena cava, for prevention of pulmonary embolism in patientswith a propensity for thromboembolism.

[0005] Filters mounted to the distal end of guidewires have beenproposed for intravascular blood filtration. A majority of these devicesincludes a filter which is attached to a guidewire and is mechanicallyactuated via struts or a pre-shaped basket which deploys in the vessel.These filters are typically mesh “parachutes” which are attached to theshaft of the wire at the distal end and to wire struts which extendoutward in a radial direction on the proximal end. The radial strutsopen the proximal end of the filter to the wall of the vessel. Bloodflowing through the vessel is forced through the mesh thereby capturingembolic material in the filter.

[0006] One of the major disadvantages of present filtering devices isthat the maximal expansion diameters of the deployed filters are fixedand sometimes fail to optimally and uniformly engage the vascular wall.An operator can only estimate the diameter of the vessel of interest andchoose the filter accordingly. If the vessel, e.g., the aorta, issignificantly affected by atherosclosis, the actual luminal diameter ofthe vessel would be over-estimated. In addition to blood filteringdevices, this problem is also recognized for deployment of other medicaldevices, e.g., stents and occluders.

[0007] What is needed are simple and safe devices which facilitateplacement of other medical devices in a body cavity, such as arteriesand veins, and can be variably adjusted to ensure optimal placement ofthe medical devices. Existing devices are inadequate for this purpose.

SUMMARY OF THE INVENTION

[0008] The present invention provides devices and methods for temporaryplacement of medical devices, including a filter, an occluder, and astent in a body cavity. More specifically, the invention provides aexpansion frame system, the diameter of which can be variably adjustedto facilitates, for example, insertion of blood filter for capturingembolic material in an artery or vein.

[0009] In one embodiment, the expansion frame system includes an outerwire, an inner wire, and a circular or elliptical frame. The outer wirehas a lumen communicating with a proximal end and a distal end, and isadapted to receive a percutaneous endovascular medical instrument. Theinner wire, having a proximal end and a distal end, is disposed withinthe lumen of the outer wire. The distal ends of the inner and outerwires are attached, respectively, to the frame at first and secondcircumferential points at approximately 180° from each other. Theproximal ends of the inner and outer wires can be manipulated so thatthe outer wire can be displaced relative to the inner wire, causing theframe to rotate about an axis perpendicular to the line defined by thefirst and second circumferential points. In this way, the frame can beplaced in a collapsed or an expanded condition.

[0010] In another embodiment, the expansion frame system furtherincludes a force biasing element, such as a spring, disposed about thedistal end of the inner wire. The distal region of the outer wire has anopening, through which the inner wire passes to attach to the circularor elliptical frame. The biasing element is capable of biasing thesecond circumferential point of the circular frame away from the openingof the outer wire.

[0011] In still another embodiment, the expansion frame system includesa syringe having a barrel and a plunger, where the outer wire is housedwithin a lumen of the barrel and is mounted on a distal surface of theplunger. The proximal end of the inner wire passes through the distalsurface of the plunger and is mounted on the barrel. When the plunger isadvanced slideably in the lumen of the barrel, the outer wire isdisplaced relative to the inner wire, causing the frame to rotate aboutan axis perpendicular to the line defined by the first and secondcircumferential points. In other embodiments, the proximal end of thebarrel includes a locking mechanism, capable of fixing the displacementof the plunger relative to the barrel.

[0012] In certain embodiments, an occluding device, such as anon-permeable membrane, is mounted on the frame. When in use, themembrane provides isolation of blood flow in a vessel, e.g., isolationof aortic blood flow during cardiopulmonary bypass. In otherembodiments, a filtering device, e.g., a parachute, basket, or scroll,is mounted on the frame, and a mesh is disposed over the frame. Thefiltering device may include an inflation seal for achieving bettercontact with the vascular walls. The construction and use of anassociated filter mesh have been thoroughly discussed in earlierapplications including Barbut et al., U.S. application Ser. No.08/533,137, filed Nov. 7, 1995, Barbut et al., U.S. application Ser. No.08/580,223, filed Dec. 28, 1995, Barbut et al., U.S. application Ser.No. 08/584,759, filed Jan. 9, 1996, Barbut et al., U.S. application Ser.No. 08/640,015, filed Apr. 30, 1996, Barbut et al., U.S. applicationSer. No. 08/645,762, filed May 14, 1996, and, Barbut et al., U.S. Pat.No. 5,662,671, and the contents of each of these prior applications areexpressly incorporated herein by reference.

[0013] The methods of the present invention are useful for deploying amedical device within a body cavity for, e.g., protecting a patient fromembolization during an endovascular procedure. The expansion framesystem can be inserted to capture plaque and/or thrombi from thecoronary artery, aorta, common carotid artery, external and internalcarotid arteries, brachiocephalic trunk, middle cerebral artery, basilarartery, subclavian artery, brachial artery, axillary artery, iliacartery, renal artery, femoral artery, popliteal artery, celiac artery,superior mesenteric artery, inferior mesenteric artery, anterior tibialartery, posterior tibial artery, and all other arteries carryingoxygenated blood. The expansion frame system can be usedprophylactically in patients with hypercoagulable state, includingprotein C or protein S deficiency, to prevent pulmonary embolism. It canalso be used during an endovascular procedure to prevent distalembolization of thrombi and/or foreign bodies in the venous circulation,including the superior vena cava, inferior vena cava, external andinternal jugular veins, brachiocephalic vein, pulmonary artery,subclavian vein, brachial vein, axillary vein, iliac vein, renal vein,femoral vein, profunda femoris vein, great saphenous vein, portal vein,splenic vein, hepatic vein, and azygous vein.

[0014] In a first method of using the expansion frame system, the frame,in a collapsed condition, is inserted percutaneously or through anincision into a patient's body cavity, and is advanced into a region ofinterest. The proximal end of the outer wire is retracted relative tothe proximal end of the inner wire, causing the frame to rotate about anaxis perpendicular to the line defined by the first and second points,thereby increasing its profile. In this way, the frame circumferentiallyengages the luminal wall.

[0015] When used during an endovascular procedure, e.g., percutaneoustransluminal angioplasty of a coronary or carotid artery, to provideprotection against distal embolization, the expansion frame system,having a filter mounted on the frame in a collapsed condition, isinserted through a peripheral artery into the coronary or carotid arterydistal to the occluding lesion. In using the embodiments which include asyringe, the plunger is depressed distally against the barrel, therebyretracting the proximal end of the outer wire relative to the innerwire, and placing the frame in a collapsed condition. After the frame ispositioned downstream from the occluding lesion, the plunger isreleased, moving proximally within the barrel of the syringe, therebydistancing the proximal end of the outer wire relative to the innerwire, and placing the frame in an expanded condition. The contactbetween the circumference of the frame and the luminal wall of theartery is variably adjusted to obtain optimal contact.

[0016] The angioplasty catheter carrying the angioplasty balloon at adistal end is inserted into the artery, over the outer wire in certainembodiments, and the balloon is inflated to dilate the stenotic vascularlumen. Embolic debris generated during the angioplasty procedure arecaptured by the filter mounted on the expansion frame. After adequateluminal diameter is re-established for coronary blood flow, theexpansion frame with the entrapped emboli is collapsed by depressing theplunger against the barrel of the syringe, and removed from the artery.

[0017] It will be understood that there are several advantages in usingthe variable diameter expansion frame disclosed herein for deploying amedical device. For example, the expansion frame system (1) can be usedto deploy a variety of medical devices, including a filter, stent, andan occluder, (2) can withstand high arterial blood flow for an extendedtime, (3) can be used to deploy a variety of blood filters, particularlysuited for temporary filtration of blood in any vessel to entrap embolicdebris, thereby minimizing neurologic, cognitive, and cardiaccomplications associated with distal embolization, (4) can be used withany endovascular catheter with or without an imaging device, (5) can beinserted into vessels or a body cavity of various diameter, (6) can bevariably adjusted to achieve optimal contact between the frame and theinner wall of a vessel or body cavity, and (7) can be used in adult andpediatric patients.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1A depicts an embodiment of an expansion frame systemincluding a syringe according to the present invention.

[0019]FIG. 1B depicts the expansion frame system of FIG. 1A having aframe in a collapsed condition.

[0020]FIG. 2A depicts the expansion frame system of FIG. 1B carrying afilter in a collapsed condition inserted in a vessel.

[0021]FIG. 2B depicts the expansion frame system of FIG. 2A deployingthe filter in a vessel.

[0022]FIG. 2C depicts the expansion frame system of FIG. 2A deployingthe filter in another vessel having a smaller diameter.

[0023]FIG. 2D depicts a distal view of the expansion frame system ofFIG. 2C.

[0024]FIG. 3A depicts the expansion frame system of FIG. 1B carrying amembrane inserted in a vessel.

[0025]FIG. 3B depicts the expansion frame system of FIG. 3A deployingthe membrane in the vessel.

[0026]FIG. 4 depicts an expansion frame system carrying a filterdeployed in the aorta through a side port of a cannula.

DETAILED DESCRIPTION

[0027] Although the variable expansion frame system is most useful indeploying blood filters in a patient's blood vessel as disclosed herein,it will be understood that the system can also be used to deploy avariety of other medical devices, e.g., a stent, an occluder, anendoscopic imaging device, or a manometer, in various body cavities.

[0028] In a first embodiment, the expansion frame system includes innerwire 10, outer wire 20, syringe 30, and substantially circular frame 40as depicted in FIGS. 1A and 1B. Outer wire 20 has proximal end 21,distal end 22 and lumen 25. Inner wire 10, having proximal end 11 anddistal end 12, is disposed within lumen 25 of the outer wire. Distal end12 of the inner wire and distal end 22 of the outer wire are attached,respectively, to frame 40 at circumferntial point 41 and circumferentialpoint 42. The frame is substantially circular or elliptical. Point 41 isdisposed approximately 180° from point 42. In certain embodiments, point41 is disposed approximately 30°, 45°, 60°, 90°, 120°, 135°, or anyother suitable angles from point 42. Distal region 23 of outer wire 20has an opening (not shown) through its wall, which is enclosed intubular member 49 and allows inner wire 10 to pass through. Spring 45, aforce biasing element, is disposed about distal end 12 of inner wire 10,thereby biasing point 41 away from the opening of the outer wire.Syringe 30 comprises plunger 31 slideably inserted in lumen 33 of barrel32. Proximal end 21 of outer wire 20 is mounted on distal surface 35 ofthe plunger. Proximal end 11 of inner wire 10 passes through distalsurface 35 of the plunger and is mounted on attachment 36 of the barrel.

[0029] In use, as depicted in FIG. 1B, frame 40 is collapsed byadvancing plunger 31 distally relative to barrel 32, thereby retractingproximal end 21 of the outer wire relative to proximal end 11 of theinner wire, and causing frame 40 to rotate about an axis perpendicularto the line defined by points 41 and 42. Medical devices mounted orcarried on frame 40 are placed in a collapsed condition to facilitateinsertion into a body cavity. The displacement between plunger 31 andbarrel 32 may be fixed by a locking mechanism included in a proximal endof the syringe. When frame 40 is positioned in the region of interest,plunger 31 is withdrawn, thereby placing frame 40 in an expandedcondition and deploying the medical device. The diameter of thesubstantially circular frame can be varied by adjusting the displacementbetween the proximal end of the outer wire relative to the inner wire.In certain embodiments, a radiopaque marker may be mounted on frame 40,tubular member 49, or distal regions of the inner and/or the outer wirefor verifying the position of the deployed device.

[0030] The expansion frame system of FIG. 1B is inserted in an arterydistal to atheromatous occlusion 100 as depicted in FIG. 2A. A filter,having mesh 50 is mounted on frame 40. The frame is placed in acollapsed condition to facilitate insertion through the stenoticvascular lesion. In FIG. 2B, when the filter is positioned downstreamfrom occlusion 100, frame 40 is rotated by retracting the proximal endof outer wire 20 relative to inner wire 10, thereby circumferentiallyengaging the luminal wall and expanding the filter in the artery. Thediameter of frame 40 can be varied by adjusting the displacement betweena proximal end of the outer wire relative to the inner wire to maximallyengage the frame with the vascular wall. Endoscopic procedures,including atherectomy, angioplasty, and/or stenting, can be performed onthe occlusion. Embolic materials, such as calcium, atheromatous plaque,tissue debris, and/or thrombi, are captured by mesh 50 of the filter.After adequate luminal size is achieved after the procedures, blood flowis re-established to push the embolic material toward mesh 50 and toperfuse distal organs. After completion of the procedure, theendovascular device is withdrawn. Frame 40 and the filter with thecaptured embolic debris are collapsed and removed from the vessel.

[0031] In situations where the luminal diameter of the vessel isoverestimated, i.e., the diameter of the frame exceeding the luminaldiameter, frame 40 can be adjusted to achieve maximal contact with thevessel wall as depicted in FIG. 2C. FIG. 2D depicts a distal view offrame 40 with mesh 50.

[0032] By way of example, when the filter as disclosed herein isintended for use in the aorta, the area of the mesh required for thedevice is calculated from Bernoulli's equation as described in ourearlier applications including Barbut et al., U.S. application Ser. No.,U.S. application Ser. No. 08/553,137, filed Nov. 7, 1995, Barbut et al.,U.S. application Ser. No. 08/580,223, filed Dec. 28, 1995, Barbut etal., U.S. application Ser. No. 08/584,759, filed Jan. 9, 1996, Barbut etal., U.S. application Ser. No. 08/640,015, filed Apr. 30, 1996, andBarbut et al., and U.S. application Ser. No. 08/645,762, filed May 14,1996.

[0033] In an embodiment of the filter that is to be used in the aorta,mesh with dimensions within the following ranges is desirable: mesh areais 0.004-5 in², more preferably 0.007-4 in², more preferably 0.010-3in², more preferably 0.015-2 in², more preferably 0.020-1 in², morepreferably 0.025-0.076 in²; mesh thickness is 60-280 μm, more preferably70-270 μm, more preferably 80-260 μm, more preferably 90-250 μm, morepreferably 100-250 μm, more preferably 120-230 μm, more preferably140-210 μm; thread diameter is 30-145 μm, more preferably 40-135 μm,more preferably 50-125 μm, more preferably 60-115 μm, more preferably70-105 μm, and pore size is 500 μm or less, more preferably 400 μm orless, more preferably 300 μm or less, more preferably 200 μm or less,more preferably 100 μm or less, more preferably 50 μm or less andusually larger than at least a red blood cell. In a preferred embodimentof the invention, mesh area is 2-8 in², mesh thickness is 60-200 μm,thread diameter is 30-100 μm, and pore size is 50-300 μm. In a furtherpreferred embodiment of the invention, mesh area is 3-5 in², meshthickness is 60-150 μm, thread diameter is 50-80 μm, and pore size is100-250 μm.

[0034] Once appropriate physical characteristics are determined,suitable mesh can be found among standard meshes known in the art. Forexample, polyester meshes may be used, such as meshes made by SaatiCorporations and Tetko Inc. These are available in sheet form and can beeasily cut and formed into a desired shape. In a preferred embodiment,the mesh is sonic welded or adhesive bonded into a cone shape. Othermeshes known in the art, which have the desired physicalcharacteristics, are also suitable. Anticoagulants, such as heparin andheparinoids, may be applied to the mesh to reduce the chances of bloodclotting on the mesh. Anticoagulants other than heparinoids also may beused, e.g., monoclonal antibodies such as ReoPro (Centocor). Theanticoagulant may be painted or sprayed onto the mesh. A chemical dipcomprising the anticoagulant also may be used. Other methods known inthe art for applying chemicals to mesh may be used.

[0035] The expansion frame system can be used to deploy other devices,such as non-permeable membrane 60, as depicted in FIGS. 3A and 3B. InFIG. 3A, membrane 60 is mounted on frame 40, which is placed in acollapsed condition by retracting a proximal end of outer wire 20relative to inner wire 10. When the membrane is positioned within aregion of interest in a vessel, frame is rotated to circumferentiallyengage the luminal wall. When deployed in the ascending aorta duringcardiopulmonary bypass, the non-permeable membrane provides circulatoryisolation of the coronary blood flow from the peripheral vascularsystem.

[0036] In other embodiments, the expansion frame system can be used todeploy a filter or any other device directly into the aorta through acannula having a side port as described in Maahs, U.S. Pat. No.5,846,260, incorporated herein by reference in its entirety. In FIG. 4,the expansion frame system carrying a filter having mesh 50 is insertedthrough side port 202 of cannula 200. Cannula 200 includes lumen 205which communicates with perfusion port 201. The lumen communicating withside port 202 may communicate with lumen 205, or in other embodimentsremains separate and isolated from lumen 205. When the cannula isinserted into aorta 150 during cardiopulmonary bypass, for example, port201 is positioned downstream in the aorta to perfuse peripheral organs.The filter is deployed upstream in the aorta through port 203 of thecannula to capture any embolic material generated during cardiothoracicprocedures. In still other embodiments, the expansion frame system canbe used through any vascular introducer, such as those described inMartinez et al., U.S. application Ser. No. 09/365,650, entitled MODULARACCESS PORT FOR DEVICE DELIVERY, filed Aug. 2, 1999, incorporated hereinby reference in its entirety.

[0037] The length of the inner and outer wire will generally be between30 and 300 centimeters, preferably approximately between 50 and 180centimeters. The inner diameter of the lumen of the outer wire willgenerally be between 0.05 and 0.5 centimeters, preferably approximatelybetween 0.1 and 0.25 centimeters. The diameter of the expansion framewill be capable of expansion to an outer diameter of at least 0.3 cm,more preferably at least 1.5 cm, more preferably at least 2 cm, morepreferably at least 2.5 cm, more preferably at least 3 cm, morepreferably at least 3.5 cm, more preferably at least 4 cm, morepreferably at least 4.5 cm, more preferably at least 5 cm, morepreferably at least 5.5 cm, more preferably at least 6 cm. These rangescover suitable diameters for both pediatric use and adult use. Theforegoing ranges are set forth solely for the purpose of illustratingtypical device dimensions. The actual dimensions of a device constructedaccording to the principles of the present invention may obviously varyoutside of the listed ranges without departing from those basicprinciples.

[0038] Although the foregoing invention has, for the purposes of clarityand understanding, been described in some detail by way of illustrationand example, it will be obvious that certain changes and modificationsmay be practiced which will still fall within the scope of the appendedclaims. Moreover, it will be apparent that certain features of eachembodiment as well as features disclosed in each reference incorporatedherein, can be used in combination with devices illustrated in otherembodiments. Accordingly, the above description should be construed asillustrative, and not in a limiting sense, the scope of the inventionbeing defined by the following claims.

What is claimed is:
 1. A method for deploying a medial device within abody, comprising the steps of: introducing an expansion frame into ablood vessel within the body of a patient, the expansion framecomprising an outer wire, an inner wire, and a substantially circularframe attached at a first point to a distal end of the outer wire, andattached at a second point to a distal end of the inner wire, the innerwire slideable relative to the outer wire; advancing the expansion frameto a region of interest; and retracting a proximal end of the outer wirerelative to a proximal end of the inner wire, wherein the circular framerotates about an axis perpendicular to the line defined by the first andsecond point, and the circular frame thereby circumferentially engagesthe luminal wall.
 2. The method of claim 1 , wherein the expansion framefurther comprises a filter mesh disposed about the circular frame. 3.The method of claim 1 , wherein the expansion frame further comprises animpermeable membrane disposed about the circular frame.
 4. The method ofclaim 1 , wherein the vessel is an artery.
 5. The method of claim 4 ,wherein the artery is an aorta.
 6. The method of claim 4 , wherein theartery is a carotid artery.
 7. The method of claim 1 , furthercomprising the step of performing an endoluminal procedure upstream ofthe expansion frame.
 8. The method of claim 7 , wherein embolicmaterials are dislodged during the procedure and captured by theexpansion frame.
 9. The method of claim 1 , wherein the expansion frameis introduced through an incision by direct access.
 10. The method ofclaim 1 , wherein the expansion frame is introduced percutaneously. 11.The method of claim 1 , wherein a radiopaque marker is mounted on thecircular frame.
 12. The method of claim 1 , further comprising the stepof verifying the position of the frame using fluoroscopy.
 13. The methodof claim 7 , wherein the endolumenal procedure is performed by advancingan endolumenal instrument over the outer wire.
 14. The method of claim13 , wherein the endolumenal instrument is an angioplasty catheteradapted to receive and be guided by the outer wire of the expansionframe.
 15. The method of claim 13 , wherein the endolumenal instrumentis a stent deployment catheter adapted to receive and be guided by theouter wire of the expansion frame.
 16. The method of claim 13 , whereinthe endolumenal instrument is an atherectomy catheter adapted to receiveand be guided by the outer wire of the expansion frame.
 17. The methodof claim 13 , wherein the endolumenal instrument is an imaging catheteradapted to receive and be guided by the outer wire of the expansionframe.
 18. The method of claim 15 , wherein the stent deploymentcatheter comprises: a self-expanding stent disposed about the outerwire; and a sheath disposed about the stent, wherein the sheath isretracted to release the stent.
 19. The method of claim 1 , wherein thestep of introducing the expansion frame into the vessel comprisesadvancing the expansion frame through an introducer.
 20. The method ofclaim 19 , wherein the introducer comprises a cannula.
 21. The method ofclaim 19 , wherein the introducer is a port on a cannula.
 22. The methodof claim 21 , wherein the port is separate from a lumen of the cannula.23. The method of claim 1 , wherein the inner wire is disposed withinthe lumen of the outer wire.